问题描述

最近想要将服务器上的Python2.7升级成3.x的版本时。使用了如下命令：

（1）强制删除已安装python及其关联
# rpm -qa|grep python|xargs rpm -ev --allmatches --nodeps
 
（2）删除残余文件
# whereis python|xargs rm -frv

执行命令后导致服务器上的yum命令和python命令都无法使用。出现以下报错：

[root@test ~]# python -V
-bash: /usr/bin/python: No such file or directory
 
[root@test ~]# yum
-bash: /usr/bin/yum: No such file or directory

解决方案

1.创建目录用来存放rpm包：

mkdir /usr/local/src/python

查看系统版本：

lsb_release -a

查看位数

getconf LONG_BIT

2.进入目录，使用wget分别下载python以及yum的rpm包

http://vault.centos.org/ 这个地址可以下载不同版本系统对应的包（注意：一定要和系统的版本号对应）

可以看到我们的系统版本是7.5.1804，这里下载以下文件

wget http://vault.centos.org/7.5.1804/os/x86_64/Packages/lvm2-python-libs-2.02.177-4.el7.x86_64.rpm
wget http://vault.centos.org/7.5.1804/os/x86_64/Packages/libxml2-python-2.9.1-6.el7_2.3.x86_64.rpm
wget http://vault.centos.org/7.5.1804/os/x86_64/Packages/python-libs-2.7.5-68.el7.x86_64.rpm
wget http://vault.centos.org/7.5.1804/os/x86_64/Packages/python-ipaddress-1.0.16-2.el7.noarch.rpm
wget http://vault.centos.org/7.5.1804/os/x86_64/Packages/python-backports-1.0-8.el7.x86_64.rpm
wget http://vault.centos.org/7.5.1804/os/x86_64/Packages/python-backports-ssl_match_hostname-3.5.0.1-1.el7.noarch.rpm
wget http://vault.centos.org/7.5.1804/os/x86_64/Packages/python-2.7.5-68.el7.x86_64.rpm
wget http://vault.centos.org/7.5.1804/os/x86_64/Packages/python-iniparse-0.4-9.el7.noarch.rpm
wget http://vault.centos.org/7.5.1804/os/x86_64/Packages/python-pycurl-7.19.0-19.el7.x86_64.rpm
wget http://vault.centos.org/7.5.1804/os/x86_64/Packages/python-urlgrabber-3.10-8.el7.noarch.rpm
wget http://vault.centos.org/7.5.1804/os/x86_64/Packages/python-setuptools-0.9.8-7.el7.noarch.rpm
wget http://vault.centos.org/7.5.1804/os/x86_64/Packages/python-kitchen-1.1.1-5.el7.noarch.rpm
wget http://vault.centos.org/7.5.1804/os/x86_64/Packages/python-chardet-2.2.1-1.el7_1.noarch.rpm<br>
wget http://vault.centos.org/7.5.1804/os/x86_64/Packages/rpm-python-4.11.3-32.el7.x86_64.rpm
wget http://vault.centos.org/7.5.1804/os/x86_64/Packages/yum-utils-1.1.31-45.el7.noarch.rpm
wget http://vault.centos.org/7.5.1804/os/x86_64/Packages/yum-3.4.3-158.el7.centos.noarch.rpm
wget http://vault.centos.org/7.5.1804/os/x86_64/Packages/yum-metadata-parser-1.1.4-10.el7.x86_64.rpm
wget http://vault.centos.org/7.5.1804/os/x86_64/Packages/yum-plugin-aliases-1.1.31-45.el7.noarch.rpm
wget http://vault.centos.org/7.5.1804/os/x86_64/Packages/yum-plugin-protectbase-1.1.31-45.el7.noarch.rpm
wget http://vault.centos.org/7.5.1804/os/x86_64/Packages/yum-plugin-fastestmirror-1.1.31-45.el7.noarch.rpm

3.执行以下命令，开始安装

rpm -Uvh --replacepkgs lvm2-python-libs*.rpm --nodeps --force
 
rpm -Uvh --replacepkgs libxml2-python*.rpm --nodeps --force
 
rpm -Uvh --replacepkgs python*.rpm --nodeps --force
 
rpm -Uvh --replacepkgs rpm-python*.rpm yum*.rpm --nodeps --force

说明：--nodeps --force表示仅安装当前的，不考虑安装所需的依赖

4.测试python是否可用

python命令正常

5.测试yum是否可用

yum命令正常

至此centos7.5重新安装python2.7及yum完成。